Burglar-alarm



E. E. BROWN.

BURGLAR ALARM.

APPLICATION FILED MAR. 3. 19m.

Patelited J an. 20; 1920.

ZZZBMQum UNITED STATES PATE T OFFICE.

ERNEST EMIL BROWN, 0]? DECATUR, ILLINOIS.

BURGLAR-ALARM.

Application filed March 8, 1919.

To all whom it may concern:

Be it known that I, ERNEST E. BROWN, citizen of the United States, residing at Decatur, in the county of Macon and State of Illinois, have invented certain new and useful Improvements in Burglar-Alarms, of which the following is a specification.

This invention relates to an improved burglar alarm and has as its primary object to provide a simple and effective device of this character which may be arranged 7 adjacent a door or window to be operatively connected therewith for setting off or exploding a cartridge when the door or window is opened.

And the invention has as a still further object to provide an alarm which may, when desired, or in the day time, be entirely disconnected from the door or window so that the window or door may be freely opened or closed without affecting the alarm.

Other and incidental objects will appear hereinafter. In the drawings:

Figure 1 is a perspective view showing my improved alarm operatively connected with a conventional type of door,

Fig. 2 is a vertical sectional view on an enlarged scale and more particularly showing the details of construction of the device, and

Fig. 3 is a fragmentary sectional view showing the manner in which the plunger of the device is secured in set position.

In order that the construction and operation of my improved burglar alarm may be accurately understood I have, in the drawings, shown the device in connection with a conventional type of door 10. In carrying the invention into efl'ect, I employ a base plate 11 bent at its lower end to provide a laterally directed guide lug 12. The base plate is, as particularly shown in Fig. 2, provided with a plurality of openings for receiving screws or other suitable fastening devices by which the base plate may, as shown in Fig. 1, be secured in upright position to the wall adjacent to the door. Mounted upon the upper end portion of the base plate to extend longitudinally thereof is a barrel 13 provided at its upper end with a longitudinally extending lug 14 seating flat against the base plate and secured thereto by rivets or other suitable fastening devices. A similar fastening device is employed to secure the barrel adjacent its lower end to the base plate. Riveted or Specification of Letters Patent.

Patented Jan. 20, 1920.

Serial No. 281,324.

otherwise secured to the base plate above the guide lug 12 is an angle plate 15 and slidable through the free wing of this plate as well as through said guide lug, is a plunger 16. At its upper end the plunger is preferably formed with a conical terminal while, at its lower end, the plunger is provided with a laterally directed arm 17 and formed through the plunger at a suitable point above thls arm is an opening 18. Surrounding the plunger is a helical spring 19. At its lower end this spring bears against the guide lug 12 while at its upper end the spring is engaged with a washer 20 surrounding the plunger and held against upward movement thereon by a cotter pin or other suitable fastening device 21. Thus, it will be seen that when the plunger is drawn downwardly, the spring 19 will be com pressed.

In connection with the plunger I provide a set pin 22 therefor. This pin is adapted to be removably received through the opening 18 in the plunger and is provided at one end with an eye to which is connected at one end a cord or other suitable flexible element 23. Secured to the opposite end of said cord is a hook 24 adapted to be engaged in a suitable staple 25 carried by the door 10.

In use, a. suitable cartridge is employed and this cartridge is, as conventionally shown at 26, frictionally engaged in the lower end of the barrel 13. The arm 17 of the plunger 16 is then grasped and the plunger pulled downwardly against the tension of the spring 19 when the set pin 22 is, as shown in detail in Fig. 3, engaged through the opening 18 in the plunger below the guide lug 12. The hook 24 is then engaged with the staple 25 upon the door, it being observed in this connection that sufficient slack in the cord 23 is provided so that, when desired, the hook may, before the door is closed, be engaged with the staple by a person at the outer side of the door. Consequently, should the door he subsequently opened, the resulting pull upon the cord 23 will serve to withdraw the pin 22 and release the plunger to strike the head of the cartridge so that the cartridge will thus be exploded to give an alarm. In this connection it is to be particularly noted that owing to the slack in the cord 23, the door may be opened a considerable distance before the cord is drawn taut so that under ordinary circumstances, the door will, be-

fore any pull occurs upon the cord, have gained suflicient momentum to jerk the pin 22 from within the opening in the plunger. Consequently, initial cautious opening of the door will not serve to detect the presence of the alarm in connection therewith or frustrate the ultimate actuation of the alarm. In the day time or whenever desired, the hook 242 may be disengaged from the staple 25 when the device Will be entirely disconnected from the door so that the door may be freely opened or closed without affecting the alarm. I accordingly provide a very simple type of alarm while, at the same time, the device will in use, prove thoroughly eflective. As intimated, the alarm may be employed in connection With windows but it is believed, in view of the foregoing description, that the manner in which the device will, in practice, be connected with a window, will be readily understood. Illustration in this regard has accordingly been deemed unnecessary.

As illustrated in Fig. 3 the flexible element 23 exerts an approximately longitudinal pull on the releasing pin 22 whereby the releasing pin 22 may be withdrawn from the opening 18 with a minimum of resistance. In providing means whereby the releasing pin 22 may be withdrawn without an appreciable amount of resistance, one attempting to open the door would not be advised of the presence of the alarm by the resistance of the releasing pin.

The plunger 16 is also free to rotate as the door is opened whereby the locking pin is retained approximately in line with the flexible member 23.

Having thus described the invention, what is claimed as new is:

A burglar alarm adapted for use in connection with a hinged door and including an elongated support having its lower end extended outwardly and apertured for forming a guide lug, a second guide lug secured to the intermediate portion of said elongated support, a plunger slidably extended through said guide lugs and having its lower end portion extended angularly for providing a manipulating element, a disk washer secured to the intermediate portion of said plunger, a coil spring confined between said disk washer and the first named guide lug, said plunger being provided with a transverse opening, a releasing pin extended through said transverse opening and engaged with the underside of the first named lug, a flexible element connected to said releasing pin and to said hinged door, said plunger being rotatably extended through said guide lugs, whereby when said door is swung to an open position the plunger will be partly rotated for retaining said releasing pin in alinement with said flexible element, and a signal associated with said plunger.

In testimony whereof I affix my signature.

ERNEST EMIL BROWN. *[L. s.] 

